Calculating Air Velocity In Small Pipe
Calculating Air Velocity In Small Pipe
(OP)
I have a 1/4" I.D. steel pipe with air flowing through it for glass chip removal. I need help in determining the velocity so I can calculate air usage.
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Calculating Air Velocity In Small Pipe
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RE: Calculating Air Velocity In Small Pipe
RE: Calculating Air Velocity In Small Pipe
RE: Calculating Air Velocity In Small Pipe
The actual condition will be somewhat less because you do not have a "clean" orifice, that is the flow will have the chance to develop in the immediately upstream portion of the pipe and thus there will be a velocity profile immediately upstream of the outlet, the portions nearest the pipe wall travelling slower than sonic...The density in this portion is also varying, so that analysis is more involved, but it can be solved as a function of length based on the assumption of constant entropy using ideal gas equation.
If the length of the 1/4" pipe is more than a few diameters, the result from the choked orifice equation will be significantly higher than actual.
This is probably the only portion of the pipe assembly you will need to analyze...Unless the upstream components are of similar size, its doubtful they will have any significant effect on the choke condition; they will represent a minor percentage of the total available pressure difference.
RE: Calculating Air Velocity In Small Pipe
Find the equivalent fL/d of piping. If flow can be considered as adiabatic, use the Fanno line to determine pipe entrance or exit conditions and hence flow. Check to see that choking does not occur in fittings or pipe between entrance or exit. If choking does occur, readjust your assumptions and use fanno line to point where choking occurs.